Catalytic reforming of petroleum hydrocarbons with an alumina-chromium oxide catalyst comprising boron oxide



United States Patent '0 CATALYTIC REFORMING F PETROLEUM HY- DROCARBONS WITH AN ALUMINA-CHROMIUM OXIDE CATALYST COMPRISING BORON OXIDE John Arthur Edgar Moy and Bernard Whiting Burbridge, Sunbury-on-Thames, England, assignors to The British Petroleum Company Limited, London, England, a British joint-stock corporation No Drawing. Filed Dec. 4, 1957, Ser. No. 700,564

Claims priority, application Great Britain Dec. 7, 1956 5 Claims. (Cl. 208-136) This invention relates to the catalytic reforming of petroleum hydrocarbons for the production of aromatics, motor gasoline and the like.

The catalytic reforming of petroleum hydrocarbons, for example naphtha fractions, to produce fractions of increased octane number is a well-known and established art. Various catalysts have been proposed as reforming catalysts; those most commonly employed comprise compounds of metals of group VI or group VIII of the periodic table on a support consisting of or containing aluminium oxide. Thus the conversion of aliphatic hydrocarbons to aromatic hydrocarbons has been described using a catalyst consisting of a minor proportion of chromium oxide supported on a major proportion of alumina. It has further been proposed to convert paraffinic and olefinic hydrocarbons in light petroleum fractions into aromatic hydrocarbons using a catalyst comprising a cyclizing metal compound such as chromium oxide sup ported on alumina and promoted with 2.5%-20% of a rare earth element and 6%30% of potassium or rubidium or caesium, both percentages being based on the weight of the cyclizing metal compound.

The object of the present invention is further to improve reforming processes using chromia-alumina catalyst.

According to the present invention, a feedstock consisting of or containing non-aromatic hydrocarbons is contacted with a catalyst comprising chromia, alumina and a minor proportion of boron, at a temperature of from 450 to 580 C. and a pressure up to 50 p.s.i.g. to yield a product with a higher aromatic content than the feedstock, there being no addition of hydrogen, whether extraneous or recycled, to the reaction zone.

The present process besides yielding a normally liquid product having an appreciable content of aromatics and some olefins, also produces appreciable quantities of a hydrogen-rich gas, which is available as a valuable byproduct. The term a pressure up to 50 p.s.i.g. includes atmospheric pressure or below, atmospheric pressure being, in fact, preferred. A temperature in the vicinity of 525 C. is particularly preferred and the space velocity may be from 0.1 to 1.0 v./v./hr. of liquid feedstock.

The boron in the catalyst is preferably present as an oxide and preferably there is also a minor proportion of an alkali metal compound, for example a potassium compound, particularly the oxide.

The relative proportions of the catalyst components by weight of total catalyst material stable at 1020" F., are, preferably, within the limits:

The catalyst may be used in the form of a fixed bed, a moving bed or a fluidized bed. Since it is readily regenerated by burning 01f carbonaceous deposits in a stream of oxygen-containing gas, it is particularly suitable for fluidized or moving bed processes.

The process makes available a large quantity of hydrogen-rich gas as a valuable by-product.

The feedstock used should boil within the gasoline or naphtha range, and a particularly preferred fraction consists predominantly of a mixture of C -C hydrocarbons. V

Thus according to one embodiment of the invention the feedstock may be a straight-run feedstock, particularly a lower-boiling straight-run fraction commonly known as primary flash distillate. By treatment according to the present invention gasoline blending components of high octane number and high volatility may be prepared from such feedstocks, in particular gasoline blending components having a research octane number (clear) of at least 90 and a volatility of at least 70%. evaporated at 100 C.

According to a further embodiment, the feedstock may be the product of a previous catalytic reforming process so that the present invention includes a two-stage reforming process designed to produce aromatics and high octane gasoline fractions with preferably a research octane number (clear) of the order of 100. Any convenient reforming process may be used as the first stage, but

those employing a catalyst of platinum on a support containing aluminium oxide. with or without halogen are preferred, such processes being hereinafter referred toas platinum reforming processes and the products as platinum reformates.

With a two-stage process, the whole of the reformate from the first stage may be reformed in the second stage, but since the higher boiling end is rich in aromatics which are notsusceptible to further upgrading, the reformate is preferably fractionated to give a lower-boiling relatively aromatic-free fraction which is subjected to the further treatment. Alternatively the reformate may be solvent extracted andthe raffinate or a fraction th'ereofsub jected to the further treatment. If desired, the product may be recombined with the higher boiling fraction or the solvent extract as the case may be, but it may also be combined with other high octane components for example heavy cat. cracked gasoline or alkylate.

The catalyst may be prepared by any convenient method for example, by impregnation of alumina with a solution containing chromium, boron and preferably potassium.

The invention is illustrated by the following examples:

EXAMPLE 1 A platformate was split into light and heavy fractions, the light fraction having an end boiling point of 108 C. and a research octane number (clear) of 76.1. This light platformate was further reformed under the following conditions: a

Four runs were carried out under these conditions using different catalysts as follows:

(1) 10% chromuim oxide on alumina.

(2) 10% chromium oxide on alumina with 1% cerium oxide and 1% potassium oxide.

(3) 10% chromium oxide on alumina with 1% boron on e.

(4) 10% chromium oxide on alumina with 1% boron oxide and 1% potassium oxide.

2,967,822 Patented Jan. 10, I961 3 All percentages are by weight of material stable at 1020 F. Comparative data for the four runs are shown in Table 1.

A light straight-run gasoline havingan ASTM boiling range of 41-87 C. and an octane number, research, clear, of 63.3 was treated under the followingprocess conditions:

Pressure Atmospheric Space velocity v./v./hr. 0.2 Recycle gas None Processing period ..hours 5 Runs were carried out at different temperatures using the catalysts of run 2 and run 4 of Example 1 respectively. The results are set out in Table 2 below.

Table 2 Debutanized Exit Gus Product Catalyst Temperature, C. Yield ON Flow H1001]..- (per- (Res) Rate, tent,

cent Clear s.c.f./b. percent wt.) vol.

475 86.1 82.0 853 32.7 a: as as ".2

87 cr'ce'KlAlumma We claim:

1. A process for the treatment of a feedstock consisting essentially of a mixture of C to C non-aromatic hydrocarbons to efiect a dehydrogenation or dehydrocyclization thereof comprising contacting the feedstock in a reaction zone with a catalyst consisting essentially of 5 to 25% of chromium oxide, 0.1 to 5% boron, expressed. as oxide, and balance, alumina, at a temperature of about 450 to 580 C., at a pressure not in excess of about p.s.i.g., at a space velocity of 0.1 to 1 v./v./ hr., and in the absence of added hydrogen to the reaction zone, and recovering a product having increased aromatic content.

2. A process for the treatment of a feedstock consisting essentially of a mixture of C to C non-aromatic hydrocarbons to effect a dehydrogenation or dehydrocyclization thereof comprising contacting the feedstock in a reaction zone with a catalyst consisting essentially of 5 to 25% of chromium oxide, 0.1 to 5% boron, expressedas oxide, 0.1 to 5% of an alkali metal, expressed as oxide, and balance alumina, at a temperature of about 450. to 580 C., at a pressure not in excess of about 50 p.s.i.g., at a space velocity of 0.1 to 1 v./v./hr., and in the absence of added hydrogen to the reaction zone, and recovering a product having increased aromatic content.

3. A process in accordance with claim 1, wherein the feedstock is a straight run distillate consisting of a mixture of C to C non-aromatic hydrocarbons.

4. A process in accordance with claim 1, wherein the feedstock is a portion of a catalytic reformate, said portion consisting essentially of C to C non-aromatic hydrocarbons.

5. A process in accordance with claim 1, wherein the feedstock is a portion of a platinum reformate, said portion consisting essentially of C to C non-aromatic hydrocarbons.

References Cited in the file of this patent UNITED STATES PATENTS 2,337,191 Greensfelder et a1 Dec. 21, 1943 2,404,024 Bailie et al July 16, 1946 2,409,695 Laughlin Oct. 22, 1946 2,656,304 MacPherson et al Oct. 20, 1953 2,697,684 Hemminger et al Dec. 21, 1954 

1. A PROCESS FOR THE TREATMENT OF A FEEDSTOCK CONSISTING ESSENTIALLY OF A MIXTURE OF C5 TO C7 NON-AROMATIC HYDROCARBONS TO EFFECT A DEHYDROGENATION OR DEHYDROCYCLIZATION THEREOF COMPRISING CONTACTING THE FEEDSTOCK IN A REACTION ZONE WITH A CATALYST CONSISTING ESSENTIALLY OF 5 TO 25% OF CHROMIUM OXIDE, 0.1 TO 5% BORON, EXPRESSED AS OXIDE, AND BALANCE ALUMINA, AT A TEMPERATURE OF ABOUT 450 TO 580*C., AT A PRESSURE NOT IN EXCESS OF ABOUT 50 P.S.I.G., AT A SPACE VELOCITY OF 0.1 TO 1 V./V./ HR., AND IN THE ABSENCE OF ADDED HYDROGEN TO THE REACTION ZONE, AND RECOVERING A PRODUCT HAVING INCREASED AROMATIC CONTENT. 